Implement /proc/<pid>/exe

by adding proc_set/get_exe to the proc server, making
exec call proc_set_exe, and libps call proc_get_exe. procfs can then just
retrieve the information to make the "exe" symlink.

* hurd/process.defs (proc_set_exe, proc_get_exe): New RPCs.
* hurd/process_request.defs: Likewise.
* hurd/process_reply.defs: Add skips for proc_set_exe and proc_get_exe RPCs.
* proc/proc.h (struct proc): Add `exe' field.
* proc/info.c (S_proc_set_exe, S_proc_get_exe): New functions.
* proc/mgt.c (process_has_exited): Free p->exe.
(S_proc_child): Duplicate parent `exe' into child's `exe'.
* exec/exec.c (do_exec): Call proc_set_exe when a filename is available.
* libps/ps.h (struct proc_stat): Add `exe_vm_alloced', `exe', and `exe_len'
field.
(PSTAT_EXE): New macro.
(PSTAT_USER_BASE): Change value to make room.
(proc_stat_exe, proc_stat_exe_len): New macros.
* libps/procstat.c (proc_stat_set_flags): Handle PSTAT_EXE case by calling
proc_get_exe.
* libps/spec.c (ps_get_exe): New function.
(ps_exe_getter): New structure.
(ps_fmt_spec): Add "Exe" specification.
* procfs/process.c (process_file_symlink_make_node, process_file_gc_exe): New
functions.
(procfs_dir_entry): Add "exe" entry.
* startup/startup.c (launch_core_servers): Set exe paths for startup, auth,
proc, and fs servers.
(frob_kernel_process): Set exe path for kernel task.
(S_startup_essential_task): Set exe path for exec server.

1 files changed, 17 insertions, 0 deletions

diff --git a/libps/procstat.c b/libps/procstat.c
index f6420eea..d0423410 100644
--- a/libps/procstat.c
+++ b/libps/procstat.c
@@ -956,6 +956,23 @@ proc_stat_set_flags (struct proc_stat *ps, ps_flags_t flags)
 	}
     }
 
+  /* The process's path to binary executable */
+  if (NEED (PSTAT_EXE, PSTAT_PID))
+    {
+      ps->exe = malloc (sizeof(string_t));
+      if (ps->exe)
+	{
+	  if (proc_get_exe (server, ps->pid, ps->exe))
+	    free (ps->exe);
+	  else
+	    {
+	      ps->exe_len = strlen(ps->exe);
+	      have |= PSTAT_EXE;
+	      ps->exe_vm_alloced = 0;
+	    }
+	}
+    }
+
   /* The ctty id port; note that this is just a magic cookie;
      we use it to fetch a port to the actual terminal -- it's not useful for
      much else.  */